In recent years, much attention has been paid to contactless power transmission (wireless power transfer) in which electromagnetic induction is used to make power transmission possible without a metal contact. Charging of electronic apparatuses such as a household appliance and a mobile terminal has been proposed as an application example of the contactless power transmission.
Various charging control methods in contactless power transmission have also been disclosed. For example, a method is disclosed in Patent Document 1 in which an operating state of a charging control unit of a power receiving device is maintained by performing power saving power transmission in a fully charged state. With the method disclosed in Patent Document 1, a smooth return to normal power transmission or suspension of power transmission when the power receiving device is removed while power saving power transmission is being performed can be easily realized, and therefore wasteful power consumption can be suppressed.
Also, a method is disclosed in Patent Document 2 in which a switch is provided on a power transmitting device side, and a tentative power transmission for authentication is performed based on the switch operation.